1. Field of the Invention
The invention refers to a device and a method for the automatic charging of processing stations with printing cylinders.
2. Description of the Prior Art
While being manufactured, printing cylinders for rotary printing machines are conducted to various processing stations where they are covered, for example, either with chrome or copper, or where they are polished. For this purpose, so-called automatic lines are known, e.g. from the U.S. Pat. No. 5,336,898, comprising processing steps of mostly automated kind running in accordance with a special operating program. Usually, the printing cylinders are inserted into cylinder-conveying trolleys and transported manually to an input location which includes a centering means. The printing cylinder is centered by said centering means on a so-called centerline which is the centering line for all processing stations. The operator has the possibility to enter the required processing data, such as cylinder dimensions and desired operating programs, via the input location. Thereafter, a crane approaches the input location, centers a suitable holding device by means of the bearing journals or the face of the printing cylinder, lifts the printing cylinder from the trolley and conveys it either directly to a first processing station or to a storing location where the printing cylinder is stored until the respective processing station has been cleared.
After processing, the crane transports the printing cylinder from the processing station to a storing location where the printing cylinder is stored until called by the operator. To deliver a cylinder from the automatic line, the operator must first of all find the storing location of the desired cylinder and then give the order to evacuate same via the control. Subsequently, the operator must wait at an output location which is mostly identical with the input location until the crane has taken the processed printing cylinder from the storing location and dropped it at the output location.
It is, thus, disadvantageous for the described device that on the one hand, the operator must wait while he inserts the printing cylinder into the automatic line until taken by the crane and, on the other hand, that another waiting time is required until the crane has returned the printing cylinder from the machine to the conveying trolley. Depending on the operating conditions of the device, such waiting times may be rather considerable.
It is the object of the invention to improve a device of the described kind so that undesired waiting times for the operator can be avoided.
According to the invention, this object is solved by a device comprising the features of claim 1. An inventive method has been defined in claim 11. Further advantageous developments of the invention can be learned from the dependent claims.
A device according to the invention for charging at least one processing station with at least one printing cylinder, comprising a number of stationary charging stations, each being designed as input location for inserting the printing cylinder into the device, as storing location for storing the printing cylinder before and after processing, and as output location for delivering the printing cylinder from the device after processing, and further comprising a transportation equipment for conveying the printing cylinder between one of said charging stations and the at least one processing station is characterized in that the charging stations may each receive a conveying means on which the printing cylinder is mounted in detachable manner for transportation outside the device.
This means that the storage locations known so far are now being designed so that each individual storage location may additionally also serve as input and output location, thereby allowing a fast input and output of the printing cylinder at any time, irrespective of the availability and capacity of the crane.
The conveying means may be, for example, a cylinder- conveying trolley. This allows the operator to insert the printing cylinder to be processed together with the conveying means into any input location and to enter the respective required processing data. The operator may then leave the input location, as the printing cylinder will be taken from the transportation equipment as soon as possible. After processing, the printing cylinder is returned to the same location by the transportation equipment and dropped to the conveying means where it can be stored until taken by the operator together with the conveying means.
It is especially advantageous if the charging stations each comprise a positioning means for positioning and holding the conveying means to ensure that the conveying means takes a defined position in the charging station and is maintained in this position. This is of special importance because finished printing cylinders are delivered to the conveying means automatically which requires an exact position of the conveying means.
In an especially advantageous embodiment of the invention, the positioning means comprises a brake equipment based on a magnetic principle. The conveying means, e.g. the cylinder conveying trolley, is maintained in its desired position by means of a magnet.
Preferably, the transportation equipment is a crane means comprising a cross arm or traversing saddle movable in axial direction of the printing cylinder, said cross arm being provided with a movable holding means for holding the printing cylinder at its both ends relative to the cross arm in axial direction of the printing cylinder. The holding means comprises two holding elements movably arranged towards each other and relative to the cross arm, thereby enabling that, first of all, one of said holding elements gets into contact with that side of the printing cylinder that is to be held by said element. The cross arm and the other holding element now move towards the first holding element until the other holding element gets into contact with another side of the printing cylinder. In case of correspondingly designed holding elements, e.g. in the form of clamping jaws or gripping means, the printing cylinder to be processed can be gripped firmly and lifted from the conveying means. The moving speeds of the cross arm and the other holding element are selected so that the other holding element moves relative to the cross arm at the same speed as the cross arm moves relative to the first holding element. It may thus be ensured that the printing cylinder is positioned symmetrically to the cross arm while being lifted from the conveying means.
Consequently, both holding elements move towards each other at a defined speed while the cross arm moves at the same speed towards the holding element already contacting the printing cylinder, thus causing that the holding element contacting the printing cylinder does not lose contact from the printing cylinder but stands still relative to the cylinder.
In a preferred embodiment of the invention the crane means is provided with a means for determining at least one dimension of the printing cylinder. This may be, e.g. a means as described in DE 42 24 253. The dimensions may not only refer to the cylinder diameter but also to the face lenght or the entire lenght of the cylinder.
A control means is used to enter a charging station address, the cylinder ratings and an operating program for the printing cylinder to be processed, respectively.
A method according to the invention for charging at least one processing station with at least one printing cylinder comprises the following steps:
providing a number of stationary charging stations serving as printing cylinder input, storing and output location, respectively;
providing a transportation equipment for conveying the printing cylinder between one of said charging stations and the at least one processing station;
positioning and holding a printing cylinder-carrying conveying means in one of said charging stations;
conveying the printing cylinder by the transportation equipment from the charging station to the processing station;
processing the printing cylinder in the processing station;
returning the printing cylinder from the processing station to the charging station and dropping the printing cylinder to the conveying means;
releasing the conveying means.
The method according to the invention allows the function as already described above according to which the printing cylinder can be moved to any charging station from which it is transported by the transportation equipment to the processing station. After processing and returning to the charging station, the printing cylinder is dropped to the conveying means where it is released and can be moved out of the machine.
Preferably, this method allows to process and simultaneously treat several printing cylinders, as the operator may insert further printing cylinders into the device or remove them therefrom independent of the crane operation.
It is of special advantage thatxe2x80x94after having dropped the printing cylinder to the conveying meansxe2x80x94the transportation equipment adjusts to the format of the printing cylinder to be conveyed next. This means that the holding means can already adjust itself to the following printing cylinder format even before the transportation equipment has reached the position required therefor.